Many vehicles which have been involved in accidents or collisions and have been severely damaged are often classified as being constructive total losses, because of the excessive repair cost which must be incurred to repair the vehicle. A large part of this cost often includes the amount of time necessary to pull and straighten damaged frame rails and unibody structures. Even where frame rails need to be replaced, the costs are high and substantially add to the overall expense of vehicle repair.
Most prior systems which employ frame rail pull tool devices, either cause damage to the frame rails during the pulling operation and/or require multiple repositioning of equipment. This also contributes to the cost of repairing a vehicle with front end damage far exceeding the actual value of the vehicle. Insurance companies are thus compelled to pay the vehicle owner for the value of the vehicle, rather than paying the repair shop to fix it, which costs are often far less. Nevertheless, pull tool systems remain very valuable in straightening damaged frame rails.
Collision and vehicle body and frame repair shops employ various types of frame rail pull devices, most which use vise-type gripping attachment means which are secured to the edges of the rails. These frame rail pull systems exert tensioning forces to straighten frame rail structures. The tensioning forces are substantial and, as a result, when many of the commonly used pull devices are secured to the frame rails, the tremendous forces required to straighten the rails often cause the pull tools to tear or shear the rails, thus requiring additional repair time and expense.
A different type of frame rail attachment means is found in U.S. Pat. No. 4,916,793, which shows the use of an anchor plate welded to a frame rail. The pulling apparatus is secured to the plate via a pulling chain. However, this system does not allow for multi-directional straightening and its pulling point is restricted to the welding plate which is used. U.S. Pat. No. 5,044,191 shows the use of a pull bar which extends into a frame rail. However, the bar, as disclosed, will not be able to withstand the requisite tension stresses needed to straighten a rail. Also, by this system the frame rail will be severely weakened by the applied tension forces. Further, there is no provision for securing the bar directly to the side walls of the frame rail. The bar also does not permit multi-directional pulling, without making a number of readjustments of the equipment.